School Yard Archaeological Site Worksheet
Name_______________________________________________________Period_______
Introduction
Workers are constructing a new parking lot on campus and they made some interesting
discoveries. Curious to find out what happened here they have given your science class
all of the finds to interpret.
They recovered four different layers of sediment and placed each in a separate plastic bin.
With your group you will “excavate” each layer and record your observations and details
about the artifacts you find on the Archaeological Excavation Recording Form.
Each member of your group has been given money to send 1 sample from your
excavations to a Radiometric Dating Laboratory. Use your money wisely so that you can
learn the most information you can about your site. You will need to decide which
sample to send to the lab, which dating method, and state why you chose that sample.
You will receive a lab report with information on how many radioactive atoms remain in
your sample. Using what you learned about radiometric dating you will determine the
date of the samples found in your excavations.
There are several other artifacts that you have either not chosen to send to the
Radiometric Dating Lab or they cannot be dated in this way. You will need to apply
what you have learned about relative dating to estimate how old these artifacts are in your
written interpretation of the site.
You will be writing an interpretation of the Schoolyard Archaeological Site in Part 3 of
this exercise. You will need to focus on when the artifacts and strata were deposited and
support your interpretations with the absolute and relative dates you determined and your
profile maps made while excavating.
Vocabulary:
stratigraphy: the layering of deposits. Cultural remains and natural sediments become
buried over time, forming layers or what scientists call strata (singular: stratum).
artifact: any object made or used by people that is found in archaeological sites
1
PART 1:
Archaeological Excavation Recording Form
Record your observations for each stratum. Have at least 3 quantitative and 3 qualitative
observations about the artifacts or sediments for each stratum. Include relevant
information on the attached Profile Map. You may also include drawings on the back of
the page.
Stratum 1:
Stratum 2:
2
Stratum 3:
Stratum 4:
3
4
PART 3:
Radiometric and Relative Dating Results
Your have been given money to send 1 artifact sample to the Radiometric Dating
Laboratory. Choose 1 of the artifacts recovered from your excavations to send to the lab.
The lab will provide the number of radioactive Carbon14 or Potassium40 atoms remaining.
You must use the tables and graphs provided to look up your results to determine the
years since death (for Carbon14 samples) or years since formation (for Potasium40
samples).
You will need to discuss your sample choice and dating results with the other members of
your group so that you can write up your interpretations about the site. Use your choice
wisely to learn as much as you can about the archaeological site.
Artifact Description:
Location Found:
Why did you select this artifact for dating? What do you hope it tell you about this
site?
Will the sample be submitted for Carbon14 or Potassium40 Radiometric Dating?
Why?
Number of Radioactive Atoms Remaining: _____________________________
(Ask your teacher for the results)
Age:
5
Radioactive Dating Information
Radioactive Decay of Carbon14
Years Since Death
Number of half-lives
C14 atoms remaining
passed
0
0
10,000
5,730
1
5,000
11,600
2
2,500
17,470
3
1,250
23,340
4
625
29,210
5
312
35,080
6
156
40,950
7
78
46,820
8
39
52,690
9
20
Radioactive Decay of Carbon14
12,000
C14 Atoms Remaining
10,000
8,000
6,000
4,000
2,000
0
0
5,730 11,600 17,470 23,340 29,210 35,080 40,950 46,820 52,690
Years Since Death
6
Radioactive Decay of Potassium40
Years Since
Formed (Billions
of years)
Number of half-lives
passed
P40 atoms remaining
0.0
1.3
2.6
3.9
5.2
0
1
2
3
4
10,000
5,000
2,500
1,250
625
Radioactive Decay of P40
P40 Atoms Remaining
12,000
10,000
8,000
6,000
4,000
2,000
0
0.0
1.3
2.6
3.9
5.2
Years Since Formed (Billions of years)
7
PART 3
Interpretation
After you have completed your excavation and determined the absolute dates of the
samples recovered, what do you think happened here? Discuss with your group what you
think happened in this location and in what order the artifacts were deposited. Write a
paragraph about each stratum that reconstructs in what order each of the artifacts you
recovered was deposited. List all of the absolute dates that your group obtained. Be sure
to conclude your paragraph with evidence to support why you think things were
deposited in that particular order.
Stratum 1
Youngest
To
Oldest
Why?
________________________________________________________________________
Stratum 2
Youngest
To
Oldest
Why?
8
Stratum 3
Youngest
To
Oldest
Why?
________________________________________________________________________
Stratum 4
Youngest
To
Oldest
Why?
9